Scott Walker and John Kasich are tied for third at seven percent apiece -- a significant drop for Walker from recent months and a significant advance for Kasich, who announced his candidacy on June 21. Following are Marco Rubio, at six percent; Ben Carson and Rand Paul, five percent; Chris Christie, four percent; Ted Cruz and Carol Fiorina, three percent; and the rest of the field.

The survey suggests Trump's appeal is strong across the spectrum of voters likely to go to the polls in the New Hampshire primary. Among registered Republicans, his support is 21 percent. Among independents, who are allowed to vote in the GOP primary, his support is 29 percent. Trump leads among voters who call themselves very conservative, as well as among those who call themselves somewhat conservative. Only among moderate voters does Bush lead, and even among them, Trump is just four points behind.

Trump has a huge lead among voters under 50 years old -- 30 percent to Rand Paul's 12 percent. Trump also has a solid advantage among voters over 50 -- 21 percent to Bush's 13 percent.